A comparative study on the fine structure of flight muscle of mature male and female Poekilocerus bufonius klug (orthoptera pyrogomorphidae)‎

Abstract EN

The shape and size of the flight muscles fibres of male P.

bufonius are almost uniform.

The nucleus is situated at the periphery of the fibre and contains normal distribution of the chromatin.

The myofibrils are in almost perfect transverse register, with regular Z and I bands.

The mitochondria are moderate and contain very well developed cristae.

The sarcoplasmic reticulum and its association with T-system to form dyads are well developed.

In contrast, the female flight muscle fibres are reduced in size to slender thread-like structures.

The decrease in width is due to atrophy of myofibrils so, that the surface (sarcolemma) becomes scalloped or markedly irregular.

The nuclei are located peripherally and are surrounded by undifferentiated sarcoplasm, suggesting nucleus shrinkage (Pyknosis).

The pyknotic nuclear chromatin is aggregated or climped into numerous masses occasionally adjacent to the nuclear membrane.

The myofibrils are small and the cross-stri-ations are poorly defined.

The Z-bands are irregularly arranged, or absent in some cases.

Less organized myofibrils and indistinct sarcomere bands are evident.

The mitochondria are scarce and the sarcoplasmic reticulum is abundant with clear indication of dilation.

More study is needed to ascertain whether atrophy of flight muscle of mature adult female coincides with gonad growth or the flight muscle never develop.